I am stealing @Lex-Kloet-RX his list of waypoint libraries:
( I hope you don't mind Lex! )
This inspired me to the following:
Anyone who maintains a list of POIs can make them public through the MRA website. This might look like making your routes available for anyone or just friends. This will make available a list of all publicly available POI libraries.
In this list a user can choose whatever library he wants to use, just by placing a checkmark. All maintenance done on a list by the owner, will reflect immediately to all the subscribed users.
This might look a bit like the wordpress plugin system. Select the POI libraries you like or are relevant for you, "install" them, and they are added to your planner.